SemGroup® Corporation (NYSE:SEMG) and Rose Rock Midstream, L.

SemGroup® Corporation (NYSE:SEMG) and Rose Rock Midstream, L.P. (NYSE:RRMS) will attend the 2012 Global Hunter Securities 100 Energy Conference in San Francisco, California on June 25-26, 2012. Norm Szydlowski, Chief Executive Officer, will present an overview of the businesses, commencing at approximately 9:00 a.m. Pacific Time on June 26, 2012.

A live audio webcast of the presentation along with materials used during the conference will be accessible on the SemGroup website at www.semgroupcorp.com and the Rose Rock Midstream website at www.rrmidstream.com on Tuesday, June 26, 2012.

About SemGroup

Based in Tulsa, Oklahoma, SemGroup® Corporation is a publicly traded midstream service company providing the energy industry the means to move products from the wellhead to the wholesale marketplace. SemGroup provides diversified services for end users and consumers of crude oil, natural gas, natural gas liquids, refined products and asphalt. Services include purchasing, selling, processing, transporting, terminalling and storing energy.

SemGroup® is a registered trademark of SemGroup Corporation.

About Rose Rock Midstream

Rose Rock Midstream, L.P. (NYSE: RRMS) is a growth-oriented Delaware limited partnership recently formed by SemGroup® Corporation (NYSE: SEMG) to own, operate, develop and acquire a diversified portfolio of midstream energy assets. Rose Rock Midstream provides crude oil gathering, transportation, storage and marketing services. Headquartered in Tulsa, OK, Rose Rock Midstream has operations in six different states with the majority of its assets strategically located in or connected to the Cushing, Oklahoma crude oil marketing hub.